<title>Search</title>
<form name="searchForm" action="./posting_search.php" method="post">
<table align="center">
<tr><td style="height:150px;"></td></tr>
    <tr>
        <td align="center">From </td>
        
        <td style="height:50px;">
        <input type="text" name="from" style="width:300px;"></td>
    </tr>
    <tr>
        <td align="center">To</td>
        
        <td style="height:50px;">
        <input type="text" name="To" style="width:300px;">
        <input type="button" value=" submit " onClick="searching();"></td> 
    </tr>
</table>
</form>
<script>
function searching()
{
    var sF = document.searchForm;

    if(sF.from.value == ""){
        alert("Please, Enter start point.");
        return false;
    }

    if(sF.To.value == ""){
        alert("Please, Enter end point.");
        return false;
    }
    sF.submit();

}
</script>